Posts from the ‘corundum’ Category

Did you guys know rubies and sapphires – which are usually seen in jewellery – are actually the same thing?

When I say the ‘same thing’, I mean they are both varieties of the mineral corundum, which forms mainly in metamorphic rocks, but not limited to. They have the same chemical formula, Al2O3, yet come in different colours and are known to the general public as different ‘stones’.

Rubies and sapphires both must have a certain amount of colourisation and hues to be considered a specific kind of that gemstone. Sapphires can also come in other colours than the dark blue most people know.

The reasons for all these different colours and hues is dependant on the amount of elements found within the mineral.

For example, the ruby’s pink-to-red colours are because of the presence of the element chromium.

Sapphires come in a more array of colours – blue, purple, green, yellow, pink, etc – due to different elements being present like copper, iron, and magnesium; just to name a few.

The best part is, these are all impurities. Funny how impurities actually make something even more beautiful, right? As well, we all know the diamond is the hardest gemstone, coming in with a 10.0 on the Mohs scale, but rubies and sapphires come very close with a 9.0.

Oh yeah, and these varieties can be fluorescent too. Just a bonus to add to the pure awesome that is corundum. Next time you see these gemstones set in jewellery, you’ll now know some new facts to tell others!